You might not actually have yourself it but you're sure that person next to you on the Tube has, and the one who brushed against you on the street, and omigod did I remember to sterilise my desk before I put my sandwich down... could not falling victim to the vomiting bug be even worse than actually having it?

Wednesday 9 January 2013 09:27 BST

P67 Paranorovirus Pic: Alamy

"We try to take the sting out of it,” norovirus expert John Harris told me down the line from the Health Protection Agency’s HQ, or Biological War Room. He’s not referring to the virus — a vomiting bug from which not even Henry Gray (of Gray’s Anatomy) would be able to take the sting — but the storm of scaremongering its annual visitation upon our stomachs has unleashed.

Three of my colleagues on the Standard features desk have fallen victim to the virus, one of whom picked it up at a party along with two other friends, while another threw up on the Tube, spreading discontent as well as stomach fluids among the capital’s commuters.

But, more importantly, most people who don’t have it seem to have at one time or another suspected that they were going to get it, or worried that the person opposite them on the train was infected, or just spoken idly about it because it sounds more exotic than anything else you can catch this side of the Silk Road.

Harris is right that the media enjoy a juicy health scare at a slow time of year. But what really makes the norovirus panic fly is that, while trying to calm down the rumours, the experts can’t help eulogising the virus as if they’d developed it themselves.

The Journal of Infectious Diseases concedes that it is a near-perfect human pathogen. Professor Ian Goodfellow, an expert on the virus, calls it “the Ferrari of the virus world”, and Harris himself admits that “I’ve heard virologists say that it’s probably one of the most infectious viruses known to humans”— which is the kind of line you expect to hear from implausibly good-looking leads in the first reel of an action movie.

According to the Health Protection Agency, there have been 3,877 laboratory-confirmed cases so far this autumn and winter — 72 per cent higher than at the same time last year. But after a study a few years ago indicated that 288 people tend to get the norovirus for every confirmed case, the HPA says that 1.12 million cases probably occurred in that period.

And though Harris wouldn’t be drawn on how many people may have it at any one time (the number is lower than you might expect, given that there are 63.2 million people in the UK and the virus normally lasts for a couple of days), reports of ambulances queuing outside hospitals as a result of mass contagion, and anecdotal workplace evidence, have many of us on high alert.

A columnist yesterday advised that we behave like murderers who would be guaranteed to die in jail if we left a single fingerprint anywhere. It’s an extension of the NHS advice to wash our hands frequently and avoid sharing towels and flannels, with the added murderer role-play. And because of the very low “infectious dose” required to pick up the norovirus (meaning that very few particles are required), that kind of vigilance will probably help.

Because it is a gastro-intestinal pathogen — it has to get into your stomach — hand-to-mouth transmission is the most common path. But if someone vomits close to you, the sheer volume of virus particles in the vomitus (millions, apparently) means that you could catch it in the air, too.

Though it may look like lunacy, trying to limit how many surfaces you touch on the Tube, leaving the carriage if someone throws up and disinfecting your desk before lunch is a well-justified strategy, described as “constructive paranoia” in a recent book.

It’s an attitude reported in many traditional societies, and means avoiding repeated low-risk events, such as sleeping under dead trees, in the knowledge that if you encounter them frequently enough you will at some point slip up. In his book about learning from primitive societies, The World Until Yesterday, Jared Diamond says avoiding “cumulative hazard” is important in societies where less help is available to those who are injured or unwell.

Catching the norovirus might be a statistically unlikely danger, but given that there are hundreds of moments in your day when you could encounter it, and there is no way of dodging its nausea, vomiting, cramps and diarrhoea once you have it, what’s not to be paranoid about?